With the advances in technology and medicine, implants, such as bone screws, are used to fix the biological tissue in the human body for medical purpose, for example, for repairing accidental injury or nature aging.
However, modulus of elasticity of the conventional implants (which is about 100 Gpa) is much higher than that of the biological tissue in human body (which is lower than 1 Gpa). When the force applied is too high, the tissue tends to, necrosis, wear, and the implants may also be loosened. In general, the conventional process of manufacturing implants includes a special sintering process or a surface coating process to the implants, and then executing a surface treatment by laser to enhance bone integration. But the conventional process has limitation for improving the stress shielding effect of the implants. And the small size of implants may also increase the difficulty in a traditional process.